i suck at theory and have come a long way with it in just a few months but i'm still confused a little. if somebody gives me a key or chord i can always make something sound good over it but i'm never sure that i'm thinking of all of the possibilities. let's say somebody called out a D7 vamp. how can you assume what key it's in? or do you not have too? what is the basic scale form for a D7 chord? i always just think in terms of a major or minor scale and then figure out what sounds good by trial and error but it seems that there should be a way to THINK over it. i just don't know all of the rules yet. is there a simple way to know what to use over the basic jazz chords? Maj7, m7, b5, 7? thanks.